The skis used for alpine skiing are constituted by relatively long boards on which the skier's boots are held in place by a front and a rear binding. The boots and bindings are positioned in the central zone of the ski, commonly called the runner.
It is known that, when the bindings are assembled directly to the ski, the sole of the boot exerts a stiffening action on the ski, in the area of the runner. Moreover, the bindings exert a clamping action on the boot sole, the reaction to which is transmitted to the ski.
The flection of skis of this type is, therefore, affected by the boot and the bindings.
Some binding assemblies have been designed so as to weaken to the maximum possible extent the disruptions of ski flection caused by the boot. A binding assembly of this type is, for example, disclosed in DE-OS 3 109 754.
There are also other devices which, resist ski flection either by exerting a stiffening action, or by a damping action in the runner zone, or by a combined stiffening and damping action. A device of this kind, described, for example, in EP 104 185, comprises a plate supporting the front and rear bindings and comprising a central part which is raised in relation to the upper ski surface and one end of which is attached to the ski, while the other end is connected to the ski while allowing relative longitudinal movement. Elastically-deformable blocks exert a damping action on this longitudinal movement. Furthermore, this device comprises a layer of elastically-deformable material inserted between the central portion of the plate and the upper ski surface.
This device effectively damps the flection movements of the ski, but it exerts little or no action on the vibrations to which the ski is subjected. These vibrations impair contact between the sole of the ski and the snow, and, accordingly, if these vibrations are not damped, the speed of the ski and the precision with which it is guided will not be optimal.